Method oe and apparatus eor treating material with gas



Patented .lune Z6, i923.

THEODORE NAGEL, OF BRDOKLYN,`1\TEW YORK.

METHODOF ANDPIPARATUS FOR TREATING MATERIAL I'IH` GAS.

Application led April 26, 1922. Serial No. 556,810,

To all whom t may concern Be it known that l, Trinononn Nacer.,

have invented certain new and useful lm.

provements in Methods of and Apparatus for Treating ldaterial with Gas, of which the following is a specification.

My invention relates to a method of and apparatus for treating material witha gas wherein a charge/of thematerial and a gas are continuously fed in opposed directions through a rotating cylindrical shell or chamber.

An object of the invention is the provision of a method and apparatus whereby substantially allof thegas in traversing'the chamber will be brought into contact with the charge.

A further object of my'iinvention is' to provide avmethod and apparatus .wherein the` charge will be agitated during treatment so as'to presentfcontinuously changing exposed surfaces and wherein the gas is so controlled as to direction that substantially all of the gas is passed into contact with the charge and substantially all of the particles occuo inoor iillino' a s ace about the een? y b D tral longitudinal axis thereof, the space between the periphery of the core `andthe wall of the shell being provided with a helical member surrounding the core. llhis con-` struction enables me to continuously advance a charge of material through the shell whilel the charge is being constantly agitated, a practically uniform helical annular motion being imparted to the gas passing through the shell in the oppositedirection, thereby, as I have above `pointed out, forcing substantially all of the gas at each revolution of the gas to contact with the charge and to presentevery particle of the charge to the gas duringvthe passage of the charge through the shell. i

In the accompanying drawingsf Fig. l illustrates in sectional elevation an embodiment of my invention;

Fig. 2 is a section 'through Fig. l, on `the Fig. `3 `illustrates in section a. form of apparatus on which my invention is an improvement; y

Fig. l is a longitudinal section through another form of apparatus; and

Fig. 5 is a section through anapparatus such as shown in Fig. fl. y

In order that my invention maybe clear ly understood l will describe the same `in connection with the reduction of metallic oxids, without limiting'myself tothe treatment of such materials, however, and l will point out briefly the difliculty experienced in present-day practice and whichl have overcome by the present invention'.

Usually a rotary furnace is employed the furnace being slightly tilted vdownwardly in the direction of advancement of. `the charge in order to effect the desired forward translation of the charge, and a reducing gas is passed through the furnace in a di?" rection opposed to the advance of the charge. However, as l have illustrated in Fig". 3, only asinall percentage of the reducing gas comes into Contact with the surface of the charge owing to the fact that the gasis free rotatable cylindrical shell tilted downward lyin the direction of advancement of the charge andl 3 a charge of material passing therethrough..k ln such a device the rela tive proportion of the gas which comes into` Contact with the `surface of the charge to thegas passing through the free area which does not come into contact with the surface `of the charge is represented by the shaded area designated l and the unshaded area designated 23 respectively in Fig. 3, andthe distance the gas has to travel is merelyv the length of the shell 2.

To overcomev the necessity of tilting the shell an apparatus `similar `to thatfillustrated in Fig. ,a has been proposed,` this appara'- such as `would be formed by twisting a riby bon spirally around the central axis of the cylinder 5 while maintainingthe width of Athe inside of the furnace then the mean average distance travelled by all of the gas to pass through 'the furnace is about one and one-half times the length of the furnace. This distance would be increased to about three times the length of the furnace if the pitch between the spiral walls be equal to the radius of the inside of the furnace.

The motion of the gas passing through suchv an apparatus is diagrammatically illustrated in Fig. 5 from which it will be seen that while some of the gas is passed into contact with the charge 8 a large proportion of the gas, however, has a free spiral passage through the furnace and hence is not forced to impinge against the surface of the charge at all. The relative proportion of the gas contacting with the surface ,of the charge toy that proportion of the gas which is not forced to contact with the surface of the charge is shown by the areas represented by the unshaded annulus designated 9 and the shaded circle designated 22 respectively in Fig. 5.

It will `be seen therefore that the eiliciency of the devices of Figs. 3, 4 and 5 .is

. very low due to the fact that a large pr0 portion of the gas passing through the shell is not forced to contact with the surface of the charge.

In myv improved construction I provide a rotatable shell or chamber l() within which I provide a cylindrical core 11 extending longitudinallyof the shell and surrounding the central axis of ther shell. In other words, this core occupies the space desig-4 nated 22 in Fig. 5 and prevents a-flow of gas through this space. Surrounding this core I providea helix 12 occupying. the space 13 betweenthe inner wall of the shell or v chamber 10 and the periphery of the core 11,

thepitch of this helix being such'as to formaI continuous free or open helical circular path 14 as seen in Fig. 2. The shell 10 is conveniently mounted for rotation on rollers 15, the entire apparatus which may be driven in any suitable manner rotating as a unit. The charge of material may be fed in to the furnace from a hopper 16 which is provided with a valve 17 the charge advancing through the shell from right to left as viewed in Fig. 1. At the left hand end of the shell I provide means 18 for supplying a continuous flow of gas which travels through the shell from left to right as viewed in Fig. 1. The discharge of treated material, from the shell is accomplished by a discharge chute 19 controlled by sealing valve 20.

' It will be apparent from the foregoing that with a gas being fed continuously through my improved apparatus in a direction opposed to the directionof travel or continuous advance of the charge the gas will be caused to take a practically uniform helical annular paththrough the passage 14 so as to force substantially all of the gas during each helical advancement or revolution of the gas to contact with the surface of the charge 21 due to the fact as above pointed outthat the free space designated 22 in Fig. 5 is occupied by the core 11. p

lt will be apparent also that in translating the charge forward due to the helix 12 in cooperation with the rotation of the shell 10 the surface of the charge will be constantly changing on account of the rotation of the shell 10 so that not only is all orsubstantally all of the gas passed into contact with the charge by reason of the presence of the core 11 and helix l2 but substantially all of the particles of the charge are brought f into contact with the gas inasmuch as all the particles are brought to the 'surface whilev the charge is passing through the apparatus. In this way it is obvious that I very materially increase the efliciency of the vapparatus over an apparatus of the types such as diagrammatically illustrated in Figs. 4: and

5. rIhis will bey clearly seen from a comparison of Fig. 5 with Fig. 2, the gas shown in the space 22 of Fig. 5 being practically wasted.

My invention possesses a further yadvantage over present devices `in that the free space 24 between the periphery or surface of the core 1l and the surface of the charge 21 inlay be regulated so as to give tothe volume of gas circulating throughy the shell the de-v sired velocity required for the gas while in contact with the surface of the charge;V

It will be apparent also that by providing the core llas well as ythe helix 12r the velocity of impact of the gas upon the charge is increased, thereby increasing the rate of heat transfer from the gas to the charge for the same time period of contact as compared with devices such as illustrated in Figs. 3

and 5.

I claim:

1. The method which consists in"4 advancing a charge of material and a gas through a chamber horizontally `and in opposite rections, all of the `gas at all times during its passage through the chamber flowingin practically a uniform helical, annular path, to force substantially all of the gas vduring each helical advancement thereof to contact with the charge and to present every par* ticle oit the charge to the gas during its pas-r sage through the chamber.

2. In an apparatus of the class described, a cylindrical member or shell, a cylindrical member within said shell extending longitudinally thereof and spaced from the walls thereof and a helical member within the space between the shell and said cylindrical member, said cylindrical members and said helical member being rotatable as a unit.

3. ln an apparatus of the class described, the combination of a shell, an imperforate helical wall occupying the space between the interior oi the shell and said core, said shell,

core and helix being rotatable as a unit, said apparatus being provided with a gas inlet and a material inlet whereby gas andy a charge of material may pass through the apparatus in opposed directions, said shell `in cooperation with said helix translating the member within said shell extending longitu-` dinally thereof and spaced from the walls thereof, and a helical member within the space between the said shell and cylindrical member, said shell and helix being rotatable 'Il as a. unit.

This specication signed this 22d day of April, 1922.

THEODORE NAGEL. 

